Presentation
Recurrent attacks of abdominal pain and jaundice.
Patient Data
Main findings include:
Porta-hepatis soft tissue mass is seen encasing the common bile duct (CBD) yet not occluding it. It also encases the patent hepatic artery without occlusion. The mass extends along the hepatic ducts. The mass elicits a low signal on T1WI, a high signal on T2 WI with no diffusion restriction. The mass shows delayed contrast enhancement.
The pancreatic head appears rather swollen showing a heterogeneous signal and enhancement pattern.
Occluded portal, splenic and superior mesenteric veins.
The spleen shows linear hypointense scars, compatible with prior splenic infarcts.
MRCP images showed alternating stenotic and dilated segments involving the CBD and the intra-hepatic biliary radicles, suggestive of sclerosing cholangitis.
The CT shows similar findings to the MR, with additional retroperitoneal soft tissue thickening encasing the inferior mesenteric artery with no arterial occlusion. There are also multiple enlarged peripancreatic, celiac and para-aortic lymph nodes.
The patient had a PET-CT scan which shows low-grade metabolic activity similar to hepatic metabolic activity.
Laboratory workup revealed elevated serum immunoglobulins, elevated serum IgG and IgM, elevated serum IgG4 level, and elevated ANCA (cytoplasmic).
The patient later proceeded to have US-guided biopsy of the porta hepatis mass.
No malignancy detected.
Case Discussion
This is a very interesting case which illustrates almost every abdominal manifestation of IgG4 related disease, including:
- biliary involvement, in the form of sclerosing cholangitis
- focal head pancreatitis which elicits heterogeneous signal and heterogeneous enhancement
- porta-hepatis soft tissue mass encasing the patent CBD and hepatic artery with no diffusion restriction on DWI or increased metabolic activity on PET-CT and proved to be an inflammatory mass on biopsy
- retroperitoneal soft tissue thickening (fibrosis) encasing the inferior mesenteric artery
- vasculitis with occlusion of the main veins (portal, splenic and superior mesenteric veins)
IgG4 is a chronic multi-organ fibroinflammtory disease with pancreatico-biliary involvement. 1
IgG4 can lead to synchronous or metachronous mass-forming lesions in almost any organ, more commonly in bile ducts, pancreas, kidneys, retroperitoenum, lungs, orbits, salivary or lacrimal glands. Fibrosis in these lesions leads to permanent organ damage.1
Diagnosis depends mainly on three factors:
- typical imaging findings
- elevated serum IgG4 levels
- the presence of IgG4-positive plasma cells in the affected tissues